Hard drive is probably doing much more error correcting than it needs to be doing.  I would suggest grabbing SpinRite from GRC.com.  It's not accessible, as it launches as its own operating system etc, but it might work.

But, honestly, a 4-year-old-computer.  Get a new one.

Well, my laptop is giving me problems too, though not as serious. Not to mention the microphone port seems to be spoiled as I can't use microphones on this laptop, and the laptop doesn't detect batteries and therefore didn't charge them, let alone allow me to use it when the battery is put in. I won't change my laptop yet, however, since I don't need to use a microphone much, and I would prefer to use plugs more than using batteries.
As for performance problems, my laptop often lags when using facebook, and various other apps. Not as serious as yours though it lags badly in the downloads folder for my user acount when i start moving from one item to the next and NVDA just give those progress bar beeps. The strange thing is that once the NVDA beeps stop, the lag stops as well.

Your choices are basically reinstall windows or get a new computer.  In the case of a 4-year-old computer, budget or not, you're probably sitting at the point where you may have no choice.  Debugging it via an online forum is not going to work, especially if you'e already taken it to professionals.  If I was going to do anything, and I'm not saying I could, I'd have to physically be at the machine.
My Alienware from around the same time, maybe a bit older, was top-notch.  At the time, it was the most powerful laptop you could get, and we paid an arm and a leg and a head for it.  My mid-range Macbook, costing almost 6 times less, is just about as powerful, and if you get a windows computer it's even cheeper.  While it is true that computer speed increases are slowing, they're still not linear.  Your needs may not be met by the machine for the simple reason that microsoft and other companies expect and want you to have a newer one; as a consequence, they write software to use more power (mainly by making it look better/at a higher resolution, etc).  Your computer from 4 years ago is probably 16 or more times less powerful than a computer from right now at the same price you originally paid.  This is not all quantified in numbers, or at least not the numbers you think; going into that is a major trip down computer architecture lane and probably beyond the scope of this thread.
I'm not saying run to the store.  I'm simply saying that it might be the only thing you can do.  What kind of software do you run on a daily basis?  That might say a lot; then again, it might not.

hi,
this article seems to explain the differences between processor  generations
http://www.itechtics.com/processor-generations/

Well poster 9, do you have a desktop? For some reason it seems desktops last quite a bit longer than laptops. I have a friend who has had a desktop since like 07 that still works, meanwhile my previous personal computer lasted 3 years before it kicked the bucket.

hi cx2,
nothing is running in the background except antivirus and nvda
my pc came with win7 but I purchased 8

Clock speed isn't really changing these days, it's the processor architecture where the performance gains are coming from. For this reason I'd suggest anyone looking for a new system with good performance avoid the I3 in the same way they would have been best avoiding the Celeron, with quad core being preferable where possible. For the most part the difference between different clock speeds on an otherwise identical chip won't be noticeable for our purposes, especially for audio games and general Windows tasks.

I didn't consider SSDs in this because that isn't a part of processor performance, it's always possible to fit an SSD to an older system as well. Of course for laptops an SSD is a significant trade off compared with a spinning hard drive's sheer capacity, external drives aren't always convenient and cloud services aren't always available due to coverage issues which vary depending on where you live.

Have you tried running a cleaner program like CCleaner to see if there's anything clogging up your system? I know Win 8 may be having a negative effect as well but I'm not sure how severe that would be.

Did you try CCleaner's registry cleaner option as well? I also assume you've defragmented your hard drive at some point?

hi,
since I got a new laptop this topic is irrelevent
however I have a question
this laptop comes with 4 gb ram, 465 gb ssd, nvidia 2 gb graphics  and a intel core i5 4200m processor at 2.50 ghz
my question is:
is windows 8 more suitable for this laptop?
I temperarily installed 7 on it
I read in the microsoft lisence agreement that I can only use my windows 8 lisence on 1 pc
so apparently before I put my copy of windows 8 on this pc I need to uninstall it from my other pc
so will it give me a error when I input my key on this pc
how does microsoft know you removed windows from your other pc

Holy crap that's one huge SSD.